Answer:
The value of [tex]s_{26}=84.5[/tex]
Step-by-step explanation:
We have given [tex]a_{14}=4.1[/tex]
d=1.7
We have to find [tex]s_{26}[/tex]
So, [tex]a_{14}=a+13d[/tex] from the formula
[tex]a_n=a+(n-1)d[/tex]
When n=14
[tex]a_{14}=a+(14-1)(1.7)=a+13(1.7)[/tex]
[tex]4.1=a+22.1[/tex]
[tex]-18=a[/tex]
[tex]a=-18[/tex]
Using the formula:
[tex]s_n=\frac{n}{2}[2a+(n-1)d[/tex]
When n=26
[tex]s_{26}=\frac{26}{2}[2(-18)+(26-1)(1.7)][/tex]
On simplification we get:
[tex]s_{26}=84.5[/tex]
